the outer limits of human performance

[PPWTF]

Humans could run 100m in 'less than 9.5s'

Humans
could still run below 9.5 seconds over 100 metres while dogs and horses
are running as fast as they ever will, according to a scientific study.

Professor Denny predicted that male 100m sprinters could one day get
the record down to 9.48s and while female sprinters' speeds have tended
to level off, they too could shave seconds off their times to cover the
distance in 10.19s.

As for marathon runners who cover a distance
of 42.195 km (26 miles 385 yards), Professor Denny says men could cut
the current world record by up to 4min 23s, and women by just under
three minutes.

http://www.telegraph.co.uk/scienceandtechnology/science/sciencenews/3532331/Humans-could-run-100m-in-less-than-9.5s.html